Preparation of Au/β-Mo₂C catalyst with high thermal stability and its performance in the reverse water-gas shift

β-Mo₂C support was first prepared by the temperature-programmed carbonization and the Au/β-Mo₂C catalysts with different Au loadings were then obtained by using the in -situ precipitation method. The Au/β-Mo₂C catalysts were characterized by X-ray diffraction (XRD), scanning transmission electron microscopy (STEM) and nitrogen physisorption; their performance, the thermal stability at the high temperature in particular was then investigated in the reverse water-gas shift (RWGS). The XRD results reveal that the diffraction peaks appeared at 34.44°, 38.02°, 39.44°, 52.12°, 61.53°, 69.62° and 74.65° correspond to the (100), (002), (101), (102), (110), (103) and (200) planes of β-Mo₂C, respectively, whereas no characteristic peak of Au species is detected, suggesting the high dispersion of Au nanoparticles on the Au/β-Mo₂C catalysts with a low Au loading (0.1%-0.5%). The STEM results illustrate that for the Au/β-Mo₂C catalysts with an Au loading of 0.5%-2.0%, gold nanoparticles in the form of atom clusters (about 2 nm) are anchored and uniformly dispersed on the β-Mo₂C surface. The nitrogen physisorption results demonstrate that the Au/β-Mo₂C catalysts have plenty of mesopores. The catalytic evaluation results indicate that the 0.2%Au/β-Mo₂C catalyst exhibits high activity and high selectivity to CO for the RWGS reaction; moreover, after the reaction, the Au nanoparticles are still evenly dispersed and the pore structure remain intact, suggesting that the Au/β-Mo₂C catalyst owns excellent performance and high thermal stability in the he reverse water-gas shift at high temperature.